1. Field of the Invention
The present invention relates to a method of measuring a change in the density of an underground material using a gravimeter, which is possible to sequentially measure a change in distribution and leakage of an oil or a gas stored in a reservoir or carbon dioxide stored in an underground storage.
2. Discussion of Related Art
Recently, due to environmental problems such as global warming, etc., the capture of carbon dioxide and ocean, underground, and surface storage of the captured carbon dioxide have been largely researched. In methods of storing captured carbon dioxide, the ocean storage may cause the destruction of a marine ecosystem, the surface storage is still in the early stage technology due to a repository of mineral formed of fixed carbon dioxide, and the underground storage is acknowledged as a most representative storage method among them.
After the underground storage of carbon dioxide, it is necessary to regularly monitor it. While moving upward through cracks in faults or rocks, stored carbon dioxide pollutes groundwater or leaks into the air or seawater so as to affect an ecosystem. The Norwegian Energy Company performed seismic profiling after injecting 2,300,000 tons of carbon dioxide in 1999 and 4,400,000 tons of carbon dioxide in 2001 into the ground and compared the result of the seismic profiling with data in 1994 in which carbon dioxide was not injected, thereby verifying the existence of the movement of carbon dioxide after injecting the carbon dioxide.
To allow the underground storage of carbon dioxide to be invigorated, development in technology for monitoring the movement of carbon dioxide stored in the ground is required.
Also, to efficiently use fossil fuel which is being exhausted, technologies for monitoring the movement of an oil or a gas stored in a reservoir are required. Using the technologies, since it is possible to observe reserves and a change in distribution of an oil or a gas stored in a reservoir in real time during a mining process, it is very helpful to set up an underground resource mining project.